Petra?

A family member of mine was pregnant with her second child. The first was a girl Ava, but this time they didn't find out the sex of the baby and kept their baby names a secret. When she had her little girl and anounced her name was Petra the family was shocked? Ava is way popular and all the other grandchildren have very normal names ( Jane, Henry, Connor, Elliot, Allison). I think the family is just taking the name in now because she is already named so comments don't do any good now. But Berries what do you think of the name Petra? and Petra as a sister of Ava?